#include "../head.h"

class base
{
public:
    virtual void display()
    {
        cout << "base class" << endl;
    }

    virtual void pure() = 0;
};

class derived : public base
{
public:
    virtual void display()
    {
        cout << "derived class" << endl;
    }

    virtual void pure()
    {
        cout << "pure class" << endl;
    }
};

int main()
{
    base *b = new derived;
    b->pure();
    b->display();
}